In 3rd Generation Partnership Project (3GPP) that is a standardization project, a standardization process for Evolved Universal Terrestrial Radio Access (which is hereinafter referred to as EUTRA) that realizes high-speed communication has been performed by employing flexible scheduling in prescribed frequency or time units, which is referred to as an Orthogonal Frequency-Division Multiplexing (OFDM) communication scheme or a resource block.
Furthermore, in 3GPP, a study on Advanced EUTRA (which is also referred to as LTE Advanced) that realizes higher-speed data transfer has been conducted. In EUTRA, a communication system is available on the assumption of a network in which a base station apparatuses have almost the same cell constitution (cell size). However, in Advanced EUTRA, a study on the communication system has been conducted on the assumption of a network (heterogeneous wireless network or Heterogeneous Network) in which the base station apparatuses (the cells) having different constitutions are present in a mixed manner in the same area.
A study has been conducted on a technology (Dual Connectivity) in which, like in the heterogeneous network, in the communication system in which a cell (macro cell) having a great radius and a cell (small cell) having a smaller radius than the macro cell are arranged, a terminal device makes a connection to each of the macro cell and the small cell and thus performs communication (NPL 1).
For example, a study has been conducted on a method in which both sides, the base station apparatus that constitutes the macro cell and the base station apparatus that constitutes the small cell are made to have dynamic resource allocation function, in dual connectivity that is used for connecting multiple base station apparatuses. Additionally, in order to efficiently perform communication with multiple base station apparatuses (the base station apparatus that constitutes the macro cell and the base station apparatus that constitutes the small cell), each of which has the dynamic resource allocation function, a study has been conducted on extension in the terminal device of a protocol for the terminal device in such a manner that every base station apparatus is equipped with functions of data link layers (an MAC layer, an RLC layer, a PDCP layer, and the like).
Furthermore, a study has been conducted on support of transmission and reception of a radio resource control message (an RRC message) in the terminal device only between the terminal device and the base station apparatus that constitutes the macro cell. Furthermore, a study has been conducted on the need in the terminal device of a random access procedure for the base station apparatus that constitutes the small cell in order to check for synchronization in a case where the base station apparatus that constitutes the small cell and the terminal device starts to communicate with each other.
NPL 2 discloses a random access procedure in a case where the terminal device to which the dual connectivity is applied starts to communicate with the base station apparatus that constitutes the small cell. NPL 2 discloses that while the generation of the RRC message as uplink data in the terminal device in the related art triggers the random access procedure, the generation of the RRC message in the terminal device to which the dual connectivity is applied does not start the random access procedure for the small cell.
That is, because the terminal device to which the dual connectivity is applied does not transmit a RRC message to the base station apparatus that constitutes the small cell, although the RRC message is generated as transmission data, a Buffer Status Report (BSR) is not triggered because the RRC message is not regarded as a transmission buffer for the small cell. As a result, it is disclosed that a random access procedure for a Scheduling Request is not started for the small cell.